Semi-aromatic copolyamide and process for preparing same

Abstract

The invention relates to a copolyamide comprising at least two units corresponding to the following general formula: A/10,T in which: A is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine).(Cb (cyclo)aliphatic diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36; 10,T denotes a unit obtained from the polycondensation of 1,10-decanediamine and terephthalic acid, characterized in that it has a polydispersity index, denoted by Ip, of less than or equal to 3.5, measured by gel permeation chromatography. The invention also relates to the process for preparing said copolyamide, a composition comprising this polyamide and also the use of this polyamide and of such a composition.

1 . Copolyamide comprising at least two units corresponding to the following general formula:
   A/10,T   in which:   A is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine).(Cb (cyclo)aliphatic diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36;   10,T denotes a unit obtained from the polycondensation of 1,10-decanediamine and terephthalic acid,   characterized in that it has a polydispersity index, denoted by Ip, of less than or equal to 3.5, measured by gel permeation chromatography.   
     
     
         2 . Copolyamide according to  claim 1 , characterized in that it has a polydispersity index between 2 and 3. 
     
     
         3 . Copolyamide according to  claim 1 , characterized in that it comprises at least a third unit and corresponds to the following general formula:
   A/10,T/Z   in which:   the units A and 10,T are as defined in  claim 1  and   Z is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Cd diamine).(Ce diacid), with d representing the number of carbon atoms of the diamine and e representing the number of carbon atoms of the diacid, d and e each being between 4 and 36.   
     
     
         4 . Copolyamide according to  claim 1 , characterized in that A denotes a unit obtained from a monomer chosen from 10-aminoundecanoic acid (denoted by 11), 11-aminoundecanoic acid (denoted by 11), 12-aminododecanoic acid (denoted by 12) and lauryllactam (denoted by L12). 
     
     
         5 . Copolyamide according to  claim 1 , characterized in that it is chosen from 11/10,T, 12/10,T, 6,10/10,T, 6,12/10,T, 10,10/10,T, 10,12/10,T, 12,12/10,T, 11/10,T/12, 11/10,T/6 and 12/10,T/6, 11/10,T/10,I, 11/10,T/10,6, 12/10,T/10,1 and 12/10,T/10,6. 
     
     
         6 . Process for preparing the copolyamide as defined in  claim 1 , characterized in that it comprises a polycondensation step of the comonomers: monomer resulting in the unit A as defined in  claim 1 , 1,10-decanediamine and terephthalic acid, and optionally monomer resulting in the unit Z chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Cd diamine).(Ce diacid), with d representing the number of carbon atoms of the diamine and e representing the number of carbon atoms of the diacid, d and e each being between 4 and 36 in the presence of hypophosphorous acid or at least one of the salts thereof in a content between 0.05 and 3.00% by weight relative to the weight of the sum of the comonomers present in the reaction medium. 
     
     
         7 . Process according to  claim 6 , characterized in that sodium hypophosphite is used. 
     
     
         8 . Process according to  claim 6 , characterized in that the hypophosphorous acid or at least one of the salts thereof is present in a content between 0.05 and 1.00% by weight relative to the weight of the sum of the comonomers present in the reaction medium. 
     
     
         9 . Composition comprising at least one copolyamide as defined in  claim 1 . 
     
     
         10 . Composition according to  claim 9 , characterized in that it comprises at least one additive chosen from fillers, glass fibres, dyes, stabilizers, especially UV stabilizers, plasticizers, impact modifiers, surfactants, pigments, brighteners, antioxidants, natural waxes, polyolefins and mixtures thereof. 
     
     
         11 . A powder, granules, a single-layer structure or at least one layer of a multilayer structure, comprising a copolyamide according to  claim 1 . 
     
     
         12 . The powder, the granules, the single-layer structure or else the multilayer structure according to  claim 11 , in the form of fibres, a film, a pipe, filaments, a moulded article, a three-dimensional article obtained by powder agglomeration, by melting or sintering brought about by radiation, a hollow body or an injection-moulded part. 
     
     
         13 . In an additive and/or filler in paint; in coatings, in anti-corrosion compositions, in anti-abrasion compositions; in technologies for powder agglomeration by melting or sintering brought about by radiation in order to manufacture articles; in paper; in electrophoresis gels; in multilayer composites; in packaging; in toys; in textiles; in motor vehicles, in electronics; in cosmetics; in pharmaceuticals or fragrances comprising a copolyamide, the improvement wherein the copolyamide is one of  claim 1 . 
     
     
         14 . In an additive in coatings on metal parts used in the transport of fluids, on motor vehicles, in under hood coatings, or on engine parts, comprising a copolyamide, the improvement wherein the copolyamide is one of  claim 1 . 
     
     
         15 . A process for polycondensation of a copolyamide as defined in  claim 1 , comprising polycondensing said copolyamide in the presence of hypophosphorous acid in a content between 0.05 and 3.00% by weight relative to the weight of the sum of comonomers present in the reaction medium, in order to obtain a polydispersity index of less than or equal to 3.5.